Vehicle braking control device

Abstract

Provided is a vehicle braking control device applicable to a vehicle equipped with an electric-powered parking braking device, a hydraulic braking device and a regenerative braking device. The braking control device comprises a first braking control unit and a second braking control unit. When a parking braking operation is performed while the vehicle is travelling, the first braking control unit implements a first braking process which increases the braking force to the vehicle by operating the hydraulic braking device. When the braking force to the vehicle needs to be increased in a situation where the first braking process is being implemented, the second braking control unit implements a second braking process which increases the braking force to the vehicle by operating the regenerative braking device.

The invention claimed is: 
     
       1. A vehicle braking control device applicable to a vehicle equipped with a plurality of braking devices including an electric-powered parking braking device that increases a braking force to a wheel of the vehicle when a parking braking operation is performed, the vehicle braking control device comprising:
 a first braking control unit configured to perform a first braking process which increases a braking force to the vehicle by operating a first braking device of the plurality of braking devices when the parking braking operation is performed while the vehicle is traveling; and 
 a second braking control unit configured to perform a second braking process which increases the braking force to the vehicle by operating a second braking device, which is different from the first braking device, of the plurality of braking devices when there is a need to increase the braking force to the vehicle during the first braking process being performed, wherein 
 the plurality of braking devices includes a regenerative braking device configured to apply a regenerative braking force to at least one wheel of a front wheel and a rear wheel, and a hydraulic braking device configured to adjust a fluid pressure in a wheel cylinder corresponding to the front wheel and a fluid pressure in a wheel cylinder corresponding to the rear wheel, 
 in the first braking process, the first braking control unit is configured to operate the hydraulic braking device as the first braking device, thereby increasing the braking force to the vehicle by increasing the fluid pressure in the wheel cylinder corresponding to the front wheel and the fluid pressure in the wheel cylinder corresponding to the rear wheel, and 
 in the second braking process, the second braking control unit is configured to operate at least one of the parking braking device and the regenerative braking device, as the second braking device, thereby increasing the braking force to the vehicle. 
 
     
     
       2. The vehicle braking control device according to  claim 1 , wherein in the second braking process, the second braking control unit is configured to operate the regenerative braking device as the second braking device, thereby increasing the braking force to the vehicle. 
     
     
       3. The vehicle braking control device according to  claim 1 , wherein
 the parking braking device is configured to apply a friction braking force to one of the front wheel and the rear wheel and not to apply the friction braking force to the other wheel of the front wheel and the rear wheel, 
 the regenerative braking device is configured to apply a regenerative braking force to the other wheel and not to apply the regenerative braking force to the one wheel, and 
 in the second braking process, the second braking control unit is configured to increase the regenerative braking force to the other wheel by operating the regenerative braking device and then to increase the friction braking force to the one wheel by operating the parking braking device. 
 
     
     
       4. A vehicle braking control device applicable to a vehicle equipped with a plurality of braking devices including an electric-powered parking braking device that increases a braking force to a wheel of the vehicle when a parking braking operation is performed, the vehicle braking control device comprising:
 a first braking control unit configured to perform a first braking process which increases a braking force to the vehicle by operating a first braking device of the plurality of braking devices when the parking braking operation is performed while the vehicle is traveling; 
 a second braking control unit configured to perform a second braking process which increases the braking force to the vehicle by operating a second braking device, which is different from the first braking device, of the plurality of braking devices when there is a need to increase the braking force to the vehicle during the first braking process being performed; and 
 a calculation unit configured to calculate a target braking force, which is a target value of the braking force to the vehicle, in such a manner that a calculated value is to be greater as an operating amount of a braking operation member increases, wherein 
 the second braking control unit determines that there is a need to increase the braking force to the vehicle when the operating amount of the braking operation member is increased during the first braking process being performed by the first braking control unit, and performs the second braking process on the basis of the target braking force calculated by the calculation unit, 
 the calculation unit calculates the target braking force corresponding to a predetermined operating amount so that it is to be greater when the second braking process is being performed by the second braking control unit, as compared to a case in which the second braking process is not performed, 
 the plurality of braking devices includes a regenerative braking device configured to apply a regenerative braking force to at least one wheel of a front wheel and a rear wheel, and a hydraulic braking device configured to adjust a fluid pressure in a wheel cylinder corresponding to the front wheel and a fluid pressure in a wheel cylinder corresponding to the rear wheel, 
 in the first braking process, the first braking control unit is configured to operate the hydraulic braking device as the first braking device, thereby increasing the braking force to the vehicle by increasing the fluid pressure in the wheel cylinder corresponding to the front wheel and the fluid pressure in the wheel cylinder corresponding to the rear wheel, and 
 in the second braking process, the second braking control unit is configured to operate at least one of the parking braking device and the regenerative braking device, as the second braking device, thereby increasing the braking force to the vehicle. 
 
     
     
       5. The vehicle braking control device according to  claim 4 , wherein in the second braking process, the second braking control unit is configured to operate the regenerative braking device as the second braking device, thereby increasing the braking force to the vehicle. 
     
     
       6. The vehicle braking control device according to  claim 4 , wherein
 the parking braking device is configured to apply a friction braking force to one of the front wheel and the rear wheel and not to apply the friction braking force to the other wheel of the front wheel and the rear wheel, 
 the regenerative braking device is configured to apply a regenerative braking force to the other wheel and not to apply the regenerative braking force to the one wheel, and 
 in the second braking process, the second braking control unit is configured to increase the regenerative braking force to the other wheel by operating the regenerative braking device and then to increase the friction braking force to the one wheel by operating the parking braking device.